1. Field of the Invention
The present invention relates to a load port which is provided for a wafer processing apparatus for transferring various kinds of substrates (which will be referred to as “wafers” hereafter) such as silicon wafers, and which has a function of detaching/mounting a lid member (which will be referred to as “carrier door” hereafter) of a wafer storage container (which will be referred to as “wafer carrier” hereafter) for storing wafers at a predetermined pitch.
2. Related Art
Known examples of such kinds of conventional load ports include an arrangement that includes a load port door which has a function of engaging with a carrier door, and a load port door opening/closing mechanism that allows the load port door to be opened and closed, and that has a function of replacing (which will be referred to as “purging” hereafter) the atmosphere of a wafer carrier while maintaining the state in which the carrier door is opened.
Such a load port is disclosed in Japanese Unexamined Patent Application Publication No. 2003-45933 (which will be referred to as “Patent Document 1” hereafter) with reference to FIGS. 1 to 3. The load port disclosed in Patent Document 1 includes an upper wall face, a lower wall face, and an EFEM (Equipment Front End Module) door, etc., which serve as partitions between a predetermined space adjacent to the open face formed in the carrier door, and a processing space provided within a wafer processing apparatus, and has a function of purging the atmosphere of the wafer carrier through the aforementioned predetermined space.
However, with the load port disclosed in Patent Document 1, N2 gas or the like used for purging the atmosphere of the wafer carrier (which will be referred to as “purge gas” hereafter) is supplied from the side obliquely above the open face of the wafer carrier.
In some cases, this leads to a problem of insufficient supply of the purge gas to the spaces between the adjacent wafers. Now, let us consider an arrangement in which purge gas is supplied with an increased flow amount. In some cases, even such an arrangement has a difficulty in sufficiently purging the atmosphere, and could lead to higher costs for purging the atmosphere.
Furthermore, the load port disclosed in Patent Document 1 includes the EFEM mechanism that allows the EFEM door to be opened and closed. This leads to a structure in which the EFEM mechanism protrudes toward the processing space provided within the wafer processing apparatus. This results in the problem that such a structure does not conform to the so-called SEMI standard, which specifies that any protrusion should be formed with a length of 100 mm or less from the wall face of a wafer processing apparatus.